This invention relates to a fuel injector system for an internal combustion engine and more particularly to an improved cooling arrangement and construction for such an injector nozzle.
One form of fuel injection nozzle injects not only fuel but compressed air into the engine. With this type of injection nozzle, it is the normal practice to provide a housing in which a fuel injector is mounted and which forms an air chamber with the discharge of the air and, in some instances the fuel, being controlled by a solenoid operated valve. Obviously the rapid pulsation of the valve during engine operation can give rise to significant heat due to the successive energizations of the solenoid coil. The generation of said heat can give rise to a number of problems, as should be readily apparent.
Although it has been proposed to provide an air cooling arrangement for the solenoid coil, such systems have not been fully satisfactory. In the first instance, it is difficult to provide sufficient air flow for cooling. In addition, if an air cooling system is employed, there must be provided seals that preclude air leakage into the valve mechanism and past the control valve. These seals frequently must cooperate with the valve stem and thus can impede its operation.
It is, therefore, a principal object of this invention to provide an improved fuel injection system including a cooling arrangement for the actuating solenoid of the valve.
It is a further object of this invention to provide an improved arrangement for cooling the solenoid of a fuel injection system.
It is a yet further object of this invention to provide an improved arrangement for cooling a fuel injection nozzle solenoid without impeding the other operation of the mechanism.
As has been noted, one type of fuel injection system also injects air in addition to fuel into the engine. With this type of system, the air control valve is generally coaxially mounted in the injector housing and a fuel injection nozzle is mounted in this housing in a transverse relationship to the air passage. As a result, the valve stem must be relatively long between the solenoid and the actual valving element. In addition, this transverse placement gives rise to a rather bulky assembly which can, in many instances, make optimal placement of the injection nozzle difficult if not impossible.
It is, therefore, a still further object of this invention to provide an improved and compact fuel/air injection nozzle.